Advanced Materials Research Vols. 126-128

Abstract: A three-dimensional finite difference method (FDM) model of grinding temperature field for carbon fiber reinforced plastics (CFRP) was established, based on the homogenization of the thermal properties of the CFRP material. The effect of the fiber direction on grinding temperature distribution at different workpiece velocity was numerically simulated and analyzed. It is found that the effect of the fiber direction on grinding temperature field is remarkable in lower workpiece velocity but unapparent in higher workpiece velocity due to the anisotropy of CFRP material and the velocity of moving heat source. More than 230 °C surface grinding temperature, which will badly damage CFRP performance, may be produced in dry grinding according to the simulated analysis. During grinding the heat affected zone of CFRP is about 0.22 mm in depth direction. Furthermore, experimental results are well in agreement with those of the theoretical analysis.

Abstract: Amorphous NiP plate is used as a mold of precision optical parts owing to the superior machinability. In the amorphous NiP plate, some pores, whose diameter is about 100m, are generated occasionally. At present, the amorphous NiP plates with pore are rejected. However, because size of the mold becomes large in recent years, the possibility of pores becomes high. In addition, the cost of the amorphous NiP plate also becomes high. Therefore, reparation method of the pore in the amorphous NiP plate should be developed. In this paper, laser assist powder jet deposition is proposed as a reparation method of the amorphous NiP plate. And fundamental experiments are carried out.

Abstract: How to achieve the precision double-sided polishing process is a important issue for wafer manufacturing, it depends on machining condition such as machining environment, polishing speed, polishing operation mode, polishing pressure, polishing fluid etc. The key factor to the wafer surface quality is the stability of the polishing pressure. This paper analyzes the impact of double-sided polishing pressure in polishing process, using AMESim software to simulate the pressure standard deviation’s changes under diffrent polishing pressures, and carries out some experiments to identify the impact of polishing parameters (such as the ring gear ratio, polishing speed, polishing pressure) to the polishing pressure stability and the wafer surface quality.

Abstract: The wire sawing process is a highly flexible cut-off grinding process. Nowadays it is not only used in its traditional field of application (processing of natural stone) but also in the civil construction industry and for the destruction of metallic structures. In order to extend the knowledge about the process it is one goal of the Institute of Production Engineering and Machine Tools (IFW) of the Leibniz Universität Hannover, Germany, to investigate the cutting mechanisms. These are supposed to be the basis for a tool design taking into account the specific field of application. The results presented within this paper describe an approach to explain the interdependencies of the system and manipulable variables for the wire sawing process. From these interrelationships the cutting mechanisms will be derived.

Abstract: The future development of the manufacturing is using VR technology to make the machining simulation before the actual machining process made. The machining simulation of Ultra High-speed Grinding Machine Tool is researched in this paper. Firstly, using UG/NX software and VRML, the geometric modeling of machine tool is modeled. Secondly, through using Java and Javascript language, the operation and display of machining process of ultra high-speed grinding are realized. The main technologies include NC codes compiling, collision detection and material removal. Thirdly, the example of machining simulation using virtual ultra high-speed grinding machine tool can be obtained in the paper. Compared to other CNC machining simulation methods, the method in the paper has reality display, rich features, a good man-machine interaction, etc., and it does not rely on expensive CAD/CAM software. The system files generated by the machining simulation have the small size and can be transferred on the network easily.

Abstract: The polishing pad plays a significant role in the Chemical Mechanical Polishing (CMP) process and its wear influences the surface accuracy of the polished wafer. A new polishing pad wear model is introduced and the law of pad wear along the pad radius is discussed, thus a new FAP with optimized pattern is designed and prepared in order. The flatness of the wafer lapped with a uniform pattern pad and that with an optimized pattern was compared. Results show that the PV value of the latter is lower that of the former.

Abstract: Focusing on the characteristic of hard-to-grinding for viscous materials, such as titanium alloy, systemic process experiments were done about grinding viscous materials, such as TC4 titanium alloy, under the high efficiency deep grinding (HEDG). Based on the analysis to the changing and characteristic of unit area grinding force F' with maximum undeformed chip thickness hmax and equivlent cutting thickness aeq , this paper discussed the changing of its material removal mode and analyzed the changing and characteristic of grinding force ratio N, specific grinding energy es with corresponding parameters further. Then, it was analyzed about the consumption of grinding power on the process of HEDG for TC4 titanium alloy. The experiment results reveal that application of HEDG can improve machining efficiency of grinding viscous materials.

Abstract: A grinding simulation system is developed based on the technology of virtual reality. Simulation theory based on virtual reality is introduced and architecture workflow and operation of the system is studied. With the system, simulation of grinding process of all kinds of materials can be done, influence law of grinding wheel parameters (abrasive grain sizes, bond materials, grinding wheel diameter, etc.) and process parameters (grinding speed, workpiece speed, axial feed workpiece materials, etc.) on machining quality of the workpiece can be analyzed, machining quality can be forecasted and optimization of grinding process parameters can be gained.

Abstract: The technology of super-high speed point (SHSP) grinding will bring in higher precision and productivity for component manufacturing. The surface roughness attained by SHSP grinding is analyzed in this paper based on the contact area and the probability distribution of chip thickness while the swivel angle of α exists, proposing a new method to predicate the value of the roughness, the experiment of SHSP grinding is carried out whether α exists or not to verify the theoretical analysis in the paper, through observing the micro-surface after grinding, the conclusions will be drawn at last.

Abstract: A grain-arranged diamond wheel was developed and grinding performance of the wheel against aluminum alloys and titanium alloy, Ti6Al4V, has been investigated using various kinds of grinding fluid. Mirror finishing of aluminum alloys was successfully performed without grinding burn when emulsion-type grinding fluid with an extreme-pressure additive was used. When oil base lubricants or a fatty acid was supplied using a MQL supply unit, fine finishing could not be done. Mesh size of the grinding wheel had only a minor effect on surface roughness. When Ti6Al4V was ground by the developed wheel, an adhesion of work material on diamond grains occurred causing the finished surface to deteriorate.